Field evaluation of insect-resistant transgenic Populus nigra trees

The performance of insect-resistant transgenic poplar trees (Populusnigra) expressing a Cry1Ac gene from Bacillus thuringiensis subsp. Kurstaki HD-1 against poplar defoliators was evaluated in the field at the Manas Forest Station in Xinjiang Uygur Autonomous Region during1994–1997. The results showed that the average percentage of highly damaged leaves on the transgenic trees was 10% while that on the control trees in nearby plantations reached 80–90%. The average number of pupae per m² of soil at 20cm depth in transgenic poplar plantation was 18 which was only 20% of that found in the non-transgenic control field. The number of pupae and the leaf-damage on transgenic trees described above are all far below the threshold set for chemical protection measures. The non-transformed poplar trees grown in the same plantation with the transgenic trees were also protected indicating that cross protection occurred between these two kinds of trees. Insect-resistant transgenic poplar trees have a potential application value in afforestation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Survey on the contamination of Toxoplasma gondii oocysts in the soil of public parks of Wuhan, China

Toxoplasma gondii of warm-blooded animals and humans is an important pathogenic agent throughout the world. Soil is increasingly recognized as an important source in the transmission of Toxoplasma. To attain the contamination status of T. gondii in the soil of public parks, a total of 252 soil samples were collected from September 2009 to August 2010 at different sites located in 6 public parks of Wuhan, Hubei, China and detected by PCR and loop-mediated isothermal amplification (LAMP). The detection limit of PCR/B1, PCR/529 and LAMP was determined to be 50, 5, and 5 tachyzoites in soil, respectively. Forty-one samples were found positive for Toxoplasma DNA by PCR on both genes, whereas LAMP products were generated in 58 samples (χ(2)=3.6328, P=0.0567). All parks were found contaminated and no significant difference was found among the parks (PCR: χ(2)=0.0072, P=0.9325; LAMP: χ(2)=0.6101, P=0.4347). However, contamination was found with significantly different among the four seasons (PCR: χ(2)=11.6066, P=0.0007; LAMP: χ(2)=12.4636, P=0.0004), with a gradual decrease in the prevalence from spring to winter on both analyses. This is the first investigation on soil contamination of public parks in China by T. gondii oocysts. The results indicate that the soil of public parks contaminated with T. gondii oocysts may play a role in the epidemiology of toxoplasmosis and effective preventive measures should be considered. Moreover, the conventional PCR and LAMP used in the present study are applicable to detect T. gondii oocysts in soil samples.     

2017年湖南省部分猪场临床病例分析

为了解湖南省当前猪病的总体流行情况,对2017年湖南省13个市州72个规模化猪场和15个散养户送检的87例临床病例,进行了实验室诊断和流行病学分析。结果显示：该省猪群疫病多以散发形式出现,以高热、腹泻和呼吸道症状多见,气温偏低或偏高季节发病率较高,保育猪发病率高于其他生产阶段猪群,尤其是存栏量小的猪群;共检出11种病原,其中猪圆环病毒2型（PCV2）和高致病性猪繁殖与呼吸综合征病毒（HPPRRSV）检出率最高,且多以混合感染形式存在。结果表明,湖南省猪群中病毒感染较为广泛,PCV2和HPPRRSV是主要感染病原,在气温偏低和高温季节,要特别注意加强猪病防控。     

四聚乙醛亚致死剂量对福寿螺AchE、GSTs和MFO活性的影响

为了解亚致死剂量四聚乙醛对福寿螺的主要靶标酶和解毒酶活性的影响,研究了0.50mg/L的四聚乙醛处理不同时间后福寿螺不同组织中乙酰胆碱酯酶(AchE)、谷胱甘肽S-转移酶(GSTs)和多功能氧化酶(MFO)的活力变化。结果显示,四聚乙醛对福寿螺具有良好的杀灭效果,96hLC50为3.856mg/L,安全浓度为0.039mg/L;在用0.50mg/L的四聚乙醛处理的24h内,福寿螺鳃和腹足内AchE酶活力分别升高到未处理时的1.565和1.481倍而后下降,肝和肠组织内AchE酶活力分别下降为未处理时的0.132、0.282倍而后升高;不同组织中GSTs酶活力均呈现为"降低—升高—降低"的趋势;不同组织内MFO酶活力均为先下降后上升的趋势。研究表明0.50mg/L的四聚乙醛能诱导AchE、MFO和GST活性不同程度的增加,解毒酶MFO和GSTs可能在四聚乙醛的代谢中起着一定作用。     

提高真菌植酸酶热稳定性的方法

植酸酶(Phytase)能提高饲料中磷及其他养分的利用率,减少粪便中磷的排泄量,同时还能降低植酸(盐)的抗营养作用,在饲料中添加植酸酶对提高畜禽生产性能及减轻环境污染有着重要意义。真菌植酸酶具有pH作用范围广、活性高和易提纯等优点,是生产植酸酶的最佳来源。但是真菌植酸酶热稳定性普遍较低,不能完全满足饲料加工的要求。本文综述了在提高真菌植酸酶热稳定性研究方面的最新进展,讨论了其进一步的研究方向。     

甘蓝型油菜抗寒性的鉴定及相关性状的研究

１４个甘蓝型油菜品种（系）的７个抗寒性状及其与越冬抗寒性关系的研究结果表明：不同油菜品种间越冬存活率存在极显著差异,洛川１８１、甘白油菜、１６１、８４－１６等品种的越冬抗寒性强。各性状间简单相关关系都达到显著或极显著水平。偏相关分析结果表明,总含水量与束／自、总含水量与可溶性糖含量、可溶性糖含量与越冬存活率之间呈极显著或显著的负偏相关。多元逐步回归分析结果表明,总含水量对越冬存活率的偏回归系数极显著,其它性状对越冬存活率的偏回归系数都不显著,说明叶片总含水量可考虑作为油菜抗寒性鉴定的指标。     

甘氨酸铁对断奶仔猪生长性能的影响

试验选用72头杜长大断奶仔猪,随机分为3组,每组3个重复,每个重复8头。试验分为对照组Ⅰ(基础日粮含100 mg/kg无机铁)、对照组Ⅱ(基础日粮+50 mg/kg无机铁)、试验组(基础日粮+50 mg/kg甘氨酸铁),试验结果表明:对照组Ⅰ、对照组Ⅱ和试验组3个组之间差异不显著,试验组的日增重比对照组Ⅰ和对照组Ⅱ分别提高2.67%(P>0.05)和2.18%(P>0.05);从料肉比来看,试验组和对照组Ⅰ差异显著,但与对照组Ⅱ相比差异不显著。分别比对照组Ⅰ和对照组Ⅱ降低1.4%(P<0.05)和0.7%(P>0.05);在腹泻率方面,试验组与对照组Ⅰ之间差异显著(P<0.05),但与对照组Ⅱ之间差异不显著(P>0.05)。试验组比对照组Ⅰ和对照组Ⅱ分别降低93.3%和83.3%;育成率3组之间差异不显著;血清微量元素铁增加的趋势试验组均高于对照组Ⅰ和对照组Ⅱ,组间差异均不显著(P<0.05);试验组粪中微量元素铁的含量比对照组Ⅰ和Ⅱ分别降低30.02%和30.47%,且试验组和对照组Ⅰ、对照组Ⅱ之间差异极显著(P<0.01),但对照组Ⅰ和对照组Ⅱ之间差异不显著(P>0.05)。由此可见,在基础日粮中添加50 mg/kg(含二价铁)甘氨酸铁不仅能提高断奶仔猪生产性能,还能减少粪中微量元素铁的排放量。     

我国牧草种植成本收益变化与比较

本研究以牧草种植户牧草及粮食作物的调研数据为基础,计算出2010-2014年主要牧草和粮食作物的成本收益基本信息,对其变化进行统计分析,并对各作物的成本收益进行比较。分析发现,2014年苜蓿(Medicago sativa)的经济效益有所下降;黑麦草(Lolium perenne)和青贮玉米(Zea mays)的纯收益和收益率有所增长;苜蓿的纯收益和收益率要高于黑麦草和青贮玉米;马铃薯(Solanum tuberosum)和苜蓿的经济效益更具优势,种植小麦(Triticum aestivum)经济效益较差;黑麦草和青贮玉米人工和土地成本更高,苜蓿水电费最高。建议调整农业产业结构,推行粮+经+饲+草四元种植结构,全面扶持牧草产业发展,建立健全牧草生产资料补贴制度。     

阳台水培苦苣营养液配方筛选

在阳台上水培苦苣,通过测量苦苣的形态指标、叶绿素、产量和品质等指标,以期筛选出比较适合阳台水培苦苣的营养液配方。结果表明,经郑州市蔬菜研究所的营养液配方处理的阳台水培苦苣株高、叶片数、叶面积、叶绿素含量、产量、VC含量、可溶性糖含量、总蛋白质含量均显著高于其他各处理,硝酸盐含量较低。     

猪圆环病毒2型山东分离株全基因组的克隆与序列分析

根据猪圆环病毒2型(PCV-2)全基因组序列,设计一对特异性引物,从疑似断奶仔猪多系统衰竭综合征(PMWS)病料中扩增出PCV-2基因组DNA,将基因片段克隆于pMD18-T载体,筛选获得含有相应片段的阳性重组质粒pMD18-T-PCV-2。对筛选出的阳性质粒进行测序。结果表明,PCV山东株的全基因组为1 767 bp,与国内外毒株核苷酸同源性高达99.6%。